ACETO ACETIC ESTER 115 



of comparisons of the three isomeric bodies Cg Hg O 4 . They are 

 assigned the following formulae. For dehydracetic : 



CH 3 C O- C=0 



CH-CO CHCOCH 3 

 or the tautomeric forms of: 



CH 3 -C O- C=O CH 3 C O C:O 



CHC (OH) : CCOCH 3 or :- CHCO CC (OH) CH 3 . 



For a a-dimethyl-pyron-carboxylic acid : 



CH 3 C O CCH 3 

 il II 



CHCO C CO 2 H 



and for isodehydracetic acid : 



CH 3 C O C:O 



CHC(CH 3 ):CC0 2 H. 



PETERS, THEODOR, 1890. 



Ann. Chem. 257, 339-353 ; J. Chem. Soc. 58, 1097 ; Ber. 23, 468 (C). 

 Action of Alkyl Substituted Acetoacetic Esters with Ammonia. 



By the action of ammonia on these esters two products are formed 

 (i) -alkyl-/9-amido-crotonic acid, CH 3 C (NH 2 ) : CRCO 2 R, and (2) 

 amids of alkylacetoacetic acid, CH 3 COCHRCONH 2 , but the former 

 only is produced when anhydrous ammonia is employed. Ethyl- 

 acetoacetic methyl ester yields ethyl-amido-crotonic methyl ester, 

 CH 3 C (NH 2 ) : C (C 2 H 5 ) CO 2 CH 3 , which melts at 35-36, and ethyl- 

 acetoacetamid, CH 3 COCH (C 2 H 5 ) CONH 2 , melting at 96. Methyl- 

 acetoacetic ester yields methyl-acetoacetamid, CH 3 COCH(CH 3 )CONH 2 , 

 melting at 73. a-Methyl-/3-amido-crotonic ester melts at 53 Isobutyl 

 acetoacetamid melts at 88, a-isobutyl-/9-amido-crotonic ester melts 

 at 41 -42, isoamyl-acetoacetamid, CH 3 COCH (C 5 H XI ) CONH 2 , melts 

 at 129 and a-isoamyl-/3-amido-crotonic ester, CH 3 C (NH 2 ) : C (C 5 H It ) 

 CO 2 C 2 H 5 , melts at 50? Diethyl-acetoacetic ester is not attacked by 

 either anhydrous or aqueous ammonia. 



